Thermal cut-out.



No. 807,885; PATENTED DEC. 19, 1905. T. VARNEY.

THERMAL GUT-OUT.

APPLICATION FILED JAN. 3, 1905.

WlTNESSES: INVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

- THEODORE VARNEY, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A COR- PORATION OF PENNSYLVANIA.

THERMAL CUT-OUT.

Specification of Letters Patent.

Patented Dec. 19, 1905.

To all whmn it may concern.-

Be it known that I, THEODORE VARNEY, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Thermal Cut-Outs, of which the following is a specification.

My invention relates to cut-outs for electrical circuits, and particularly to devices of this general character that embody fusible conductors and supporting and protecting means therefor.

The object of my invention is to provide a thermal cut-out which shall be comparatively simple and compact in construction, the parts of which may be readily assembled, so as to be securely held against accidental displacement, and at the same time be readily detachable from each other, and in which danger of injury to the terminals of the device and to surrounding objects from arcs may be substantially eliminated.

The single figure of the accompanying drawing is a View, partially in side elevation and partially in longitudinal section, of a fuseblock and its fuse constructed in accordance with my invention.

The utilization of high-tension electrical energy, which is increasing rapidly, necessitates the employment of cut-out devices that are stronger and of more elaborate construction than those which have been heretofore employed for ordinary service. My present invention comprises structural details which specially adapt it for use in high-tension circuits, and while such structural details may be considerably varied from what I have shown and will hereinafter describe without departing from the invention I have found the present structure admirably adapted to practical service.

The fuse-block 1 is of generally cylindrical contour and comprises an outer member or shell 2, of suitable insulating material, having peripheral flanges or ribs 3 and other structural details, which will hereinafter be more fully described, and a fuse-supporting member 4, having a body portion 5, of insulating material, and a cap 6, having a handle 7. The cap 6 projects beyond the periphery of the part 2 and serves as a shield to protect the parts located beneath it from rain and snow in case the device is used out of doors, as will be generally the case.

The part5 is of screw form, and the interior of the part 2 is provided with a deep helical groove 8 to receive the corresponding thread 9 on the said part 5. The lower end 5 of the member 5 is of reduced diameter and projects through an opening 10 in the lower end of the part 2. The projection 5 is provided with a sleeve 11, of conducting material, that has a binding-screw 12, to which one end of the fusewire 13 is fastened. The fuse-wire is coiled into a helix that rests in the helical groove 14, formed between the threads 9 of the screw, and is fastened at its upper end by means of a binding-screw 15 to a conducting-plate 16, that projects laterally from the part 5 in contact with the under side of the cap or plate 6. The part 5 is provided with a longitudinal central vent-passage 17, that is connected with the helical groove 14 by means ofone or more lateral passages 18 in order to provide a suitable vent for the gases that are formed when the fuse is blown. I have shown three passages 18; but of course the number may be either greater or less than three, if desired. The part 5 projects some distance beyond the sleeve 11 in order to avoid injury to the latter by the hot gases that are ejected from the end of the vent-passage 17.

The upper end of the shell 2 is provided with a ring 19, of conducting material, that, as here shown, is angular in cross-section, so that its upper surface is engaged by the lower surface of the plate 16 when the part 5 is in its lowest position. The ring 19 is also provided with a suitable binding-post 20, to which one of the circuit-wires is connected. The lower end of the part 2 is provided with a conducting-ring 21, from which a plurality of spring contact-arms 22 project inwardly into position to be engaged by the conducting-sleeve 11 and from which projects also a suitable binding-post 23, to which the proper circuit-wire is connected.

Between the ribs or flanges 3 is located a band 24, by means of which the fuse-block may be attached to any suitable supporting structure.

It will be understood from the drawing and the foregoing description that the fuse 13 will be coiled within the helical groove or recess 14 and its respective ends attached to the binding-screws 12 and 15 and that the member 5 will be then screwed into the position shown in the drawing, in which position the parts will be securely locked together, and the engagement between members 16 and 19 and between members 11 and 22 will insure the passage of current through the fuse-wire 13.

In case a current sufliciently in excess of that which the fuse is adapted to carry passes through it it will be blown and the gases thus formed will be vented through the passages 18 and 17.

By reason of the long helical passage through which the are formed by the blowing of the fuse must pass to reach the contactterminals of the device any injury to such terminals and to adjacent apparatus is avoided.

I claim as my invention- 1. The combination with a cylinder having an internal screw-thread that extends substantially throughout its length, and end contactterminals, of a screw-shaped member provided with a helical, fusible conductor and with end contact-terminals therefor which are adapted to engage the corresponding terminals of the cylinder when said member is in operating position.

2. The combination with a shell having an interior, helical groove and provided with contact-terminals adjacent to the ends of said groove, of a screw the threads of which are adapted to engage in the said helical groove and having end contact-terminals adapted to make frictional engagement with the shell contact-terminals.

3. A cut-out for electric circuits comprising a shell having an interior, helical groove and provided with contact-terminals adjacent to the ends of said groove, a fuse-supporting member having a screw adapted to engage the helical groove in said shell and provided with a cap at one end and with contact-terminals at or adjacent to its respective ends that make frictional engagement with the shell contact-terminals when the fuse-supporting member is screwed into the shell.

4. A cut-out for electric circuits comprising a screw-shaped member having contact-terminals at or adjacent to its respective ends, a fusible conductor coiled around said member between the threads and having its ends attached to said contact-terminals, and a shell having an internal, helical groove with which the screw engages and provided with end contact-terminals.

5. A hollow, screw-shaped member having one or more lateral passages between its interior and exterior surfaces and provided with contact-terminals at or adjacent to its respective ends, a fusible conductor coiled around said member between the screw-threads and connected atits respective ends with said contact-terminals, and a shell having an interior, helical groove to receive the screw-threads of the fuse-supporting member and provided with end contact-terminals.

v 6. A cut-out for electrical circuits comprising a tubular, fuse-supporting member having an external screw-thread and one or more lateral passages between its interior and exterior and provided with contact-terminals at or adjacent to its respective ends, and an internally-serew-threaded shell having end contact-terminals and binding-posts.

7. A cut-out for electrical circuits comprising a tubular, fusesupporting member having an external screw-thread and a cap and provided with contact-terminals at or adjacent to its respective ends, in combination witha fusibleconductor helically disposed between the screw-threads and attached at its ends to the contact-terminals, and a shell having an internal, helical groove to receive the screw-thread of the fuse-supporting member and provided with end contact-terminals.

8. In a cut-out for electrical circuits, the combination with an insulating-shell having an interior, helical groove and provided with end contact-terminals, of a tubular, fuse-supporting member having an exterior screwthread adapted to engage the helical groove of the shell and provided with a cap that pro jects over and beyond the top of the shell, and a fusible conductor disposed in the form of a helix between the screw-threads and having its ends connected to contact-terminals located at or adjacent to the respective ends of the supporting member.

9. In a. cut-out for electrical circuits, the combination with an insulating-shell having an internal screw-thread and provided externally with contact-terminals and with supporting means, of a tubular, fuse-supporting member of screw form to engage the internal screwthread of the shell and having one or more lateral passages between its interior and exterior and provided with contact-terminals at or adjacent to its respective ends, and a fusible conductor helically coiled between the screwthreads and connected at its ends with the respective contact-terminals.

In testimony whereof'I have hereunto subscribed my name this 29th day of December, 190- THEODORE VARNEY.

Witnesses:

OTTO S. SOHAIRER, BIRNEY I-IINes. 

